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Fired Equipment

Fired Heater / Process Furnace

Fuel-fired process heater (box / cylindrical / cabin) — refining, petrochemical, gas.

Category
Fired Equipment
Subcategory
Process Heater
Applicable standards
7
Issuing bodies
2

Description

Fuel-fired process heater (box / cylindrical / cabin) — refining, petrochemical, gas.

Applicable Standards (7)

API — 6 standards

API 560 Fired Heaters for General Refinery Service
Edition: 5th Edition (2016, A1 2020) Region: USA, Global
Direct-fired heaters used in refining and general process service. Identical to ISO 13705.
Key requirements (10)
  • Fired heaters for refining and petrochemical service.
  • Types: cabin (vertical), box (horizontal tube radiant), cylindrical (vertical or horizontal).
  • Heat flux limits (radiant): typical 30,000 BTU/hr·ft² (95 kW/m²) for crude/vacuum; up to 50,000 for ethane cracking.
  • Tube design temperature: peak film temperature + 25 °F (14 °C) margin typical.
  • Tube life / creep: per API 530 — Larson-Miller parameter.
  • Burner sizing: 1.2 × maximum design heat release.
  • Excess air: 15% for fuel gas, 20% for fuel oil typical at full load.
  • Casing temperature: < 82 °C (180 °F) at design.
  • Flame impingement: tube clearance ≥ 1× tube OD typical.
  • Convection section: extended-surface (finned/studded) tubes; first row typically bare.
API 535 Burners for Fired Heaters in General Refinery Services
Edition: 3rd Edition (2014, R2018) Region: USA, Global
Burner design and selection for refinery fired heaters.
API 536 Post-Combustion NOx Control for Fired Equipment in General Refinery Services
Edition: 2nd Edition (2017) Region: USA, Global
SCR / SNCR NOx control for fired heaters and boilers.
API 530 Calculation of Heater-Tube Thickness in Petroleum Refineries
Edition: 7th Edition (2020) Region: USA, Global
Tube wall thickness calculation for fired heaters operating in the creep range. Identical to ISO 13704.
Key requirements (7)
  • Calculation of heater tube thickness in petroleum refineries.
  • Two design temperature concepts: elastic design (creep not governing) and rupture design (creep governing).
  • Elastic allowable stress: 2/3 yield at design temperature.
  • Rupture allowable: based on Larson-Miller parameter, typical 100,000 hr design life.
  • Permissible stress = lower of elastic or rupture allowable.
  • Tube thickness: t = P·D/(2·σ + P) for straight sections.
  • Materials: 5Cr-½Mo, 9Cr-1Mo (T9), 18Cr-8Ni (304/304H), 25Cr-20Ni (310), Alloy 800H — by service severity.
API 573 Inspection of Fired Boilers and Heaters
Edition: 4th Edition (2022) Region: USA, Global
Inspection practices for fired heaters and boilers.
API 571 Damage Mechanisms Affecting Fixed Equipment in the Refining Industry
Edition: 3rd Edition (2020) Region: USA, Global
Catalog of ~70 damage mechanisms (corrosion, cracking, metallurgical, mechanical, environmental).
Key requirements (5)
  • Catalog of >70 damage mechanisms in refining and petrochemical service.
  • For each mechanism: description, materials affected, factors, appearance, prevention/mitigation.
  • Examples: high-temp H2S corrosion, naphthenic acid corrosion, polythionic acid SCC, CUI, MIC.
  • Hydrogen damage: HTHA per Nelson curves (now revised post-Tesoro 2010 incident).
  • Used as input to RBI (API 580/581) and inspection planning.

NFPA — 1 standard

NFPA 86 Standard for Ovens and Furnaces
Edition: 2023 Region: USA
Fire and explosion safety for industrial ovens, furnaces and fired heaters.